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Section 1: Investigation, hazard assessment and remediation of existing landfills |
1 GeoCom BV, PO Box 621, 2501 CP The Hague, The Netherlands
2 Gemeentewerken Rotterdam, Galvanistraat 15, 3029 AD Rotterdam, The Netherlands
3 Delft University of Technology, Faculty of Mining and Petroleum Engineering, PO Box 5028, 2600 GA Delft, The Netherlands
The underwater sediments of the waterways, lakes and harbours of the Netherlands are sufficiently contaminated in many areas to necessitate their removal or isolation. The degree and nature of contamination and the general extent can be determined by sampling methods. To determine the thicknesses and distribution of the contaminated layers, shallow reflection geophysical surveys can be used in many situations, especially if previous erosion or dredging has created a slightly overconsolidated layer relative to subsequent deposition. The method is also used to aid investigation with respect to quantity control for sand placement to contain contaminated sediments in situ and to determine the depositional modes of hydraulically transported contaminated spoil in repository basins. Repository design for the Ketelmeer Lake allows for a certain amount of contaminant loss to the environment. The principal criterium is to significantly lessen contamination by 50%. Complete isolation would only improve the drop in contamination levels by a further small percentage.
